Fluorescent Thermometer Operating in Aggregation-Induced Emission Mechanism : Probing Thermal Transitions of PNIPAM in Water

Li Tang, Jia Ke Jin, Anjun Qin, Wang Zhang Yuan, Yu Mao, Ju Mei, Jing Zhi Sun* and Ben Zhong Tang* a Institute of Biomedical Macromolecules, Department of Polymer Science and Engineering, Key Laboratory of Macromolecule Synthesis and Functionalization of the Ministry of Education, Zhejiang University, Hangzhou, China b Department of Chemistry, The Hong Kong University of Science & Technology, Clear Water Bay, Kowloon, Hong Kong, China

The solvent peaks are marked with asterisks.refluxed overnight and quenched with 10% K 2 CO 3 .After the solvent was removed under reduced pressure, the crude product was purified with a silica gel column using a mixture of petroleum ether and ethyl acetate (20:1 v/v) as eluent.A white solid was obtained in 64.6% yield. 1  Anal.Calcd: 360.2.Found: 359.9 (M + ).
A white solid was obtained in 73.5% yield. 1

Synthesis of 1-{4-[1,2-Diphenyl-2-(p-tolyl)vinyl]benzyl}-4-(prop-1-en-2-yl)-1H-1,2,3-triazole (1).
To a round-bottom flask was added 6 (0.148 g, 0.3 mmol) and pyridine (1.5 mL).After stirring for 5 min, POCl 3 (0.092g, 0.6 mmol) was added dropwise.The reaction mixture was then stirred for 2 h at 120 o C.After cooling to room temperature, the mixture was poured into ice-water under stirring and extracted with DCM three times.The organic layer was washed with saturated aqueous CuSO 4 and then dilute hydrochloric acid, dried over MgSO 4 , and concentrated under reduced pressure.The crude product was purified by a silica gel column using a mixture of petroleum ether and ethyl acetate (1:4 v/v) as eluent.A pink powder was obtained in 71.4% yield.Copolymerization of Monomer 1 with NIPAM.The polymerization reactions were carried out under nitrogen using Schlenk techniques in a vacuum-line system except for the purification of the resulting polymers, which was done in an open atmosphere.The synthetic route to the polymers are shown in Scheme 2 and the experiment procedures are according to published literature. 2 Into a 10 mL Schlenk tube with a stopcock in the sidearm was added NIPAM (0.25 g, 2.2 mmol), 1 (in different feed, see Table

Figure S1 .
Figure S1.(A) 1 H and (B) 13 C NMR spectra of 1 in chloroform-d.The solvent and water peaks are marked with asterisks.

Figure S5 .
Figure S5.Calibration curve for determination of copolymer composition, using 1-(p-Methylphenyl)-1,2,2-triphenylethene (7) as standard.The absorbance of 7 at 322 nm was recorded in the presence of PNIPAM in THF.Concentrations of 7 and PNIPAM were 10 -5 -2 × 10 -4 M and 1 mg/mL, respectively.Open and solid circles are the data points for the standard and the copolymers, respectively.

Figure S6 .
Figure S6.(A) Photoluminescence spectra of P1c (1 mg/mL) in water/THF mixtures with different water contents (measured at ~17 °C and λ ex = 322 nm).(B) Change of PL maximum of P1c with water content of the aqueous mixture.(C) Photos of P1c in the aqueous mixtures (taken under illumination of a handheld UV lamp).

Figure S8 .
Figure S8.(A) Variation of emission spectrum of aqueous solution of P1a with its concentration (c).(B) Plots of photoluminescence intensities of P1a-P1c at 468 nm vs. solution concentration.Temperature: 21 o C; excitation wavelength: 322 nm.